36,110 research outputs found

    Polymer Segmental Cross-Correlations from Dielectric Relaxation Spectra of Block Copolymers

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    Dielectric relaxation spectra of block polymers containing sequential type-A dipoles are considered. Spectra of a specific set of block copolymers can be combined to isolate the dynamic cross-correlation between the motions of two distinct parts of the same polymer chain. Unlike past treatments of this problem, no model is assumed for the underlying polymer dynamics.Comment: 7 pages, zero figure

    Multicriteria decision making for enhanced perception-based multimedia communication

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    This paper proposes an approach that integrates technical concerns with user perceptual considerations for intelligent decision making in the construction of tailor-made multimedia communication protocols. Thus, the proposed approach, based on multicriteria decision making (MDM), incorporates not only classical networking considerations, but, indeed, user preferences as well. Furthermore, in keeping with the task-dependent nature consistently identified in multimedia scenarios, the suggested communication protocols also take into account the type of multimedia application that they are transporting. Lastly, this approach also opens the possibility for such protocols to dynamically adapt based on a changing operating environment and user's preferences

    Intelligent synthesis mechanism for deriving streaming priorities of multimedia content

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    We address the problem of integrating user preferences with network quality of service parameters for the streaming of media content, and suggest protocol stack configurations that satisfy user and technical requirements to the best available degree. Our approach is able to handle inconsistencies between user and networking considerations, formulating the problem of construction of tailor-made protocols as a prioritization problem, solvable using fuzzy programming

    Mass generation and the dynamical role of the Katoptron Group

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    Heavy mirror fermions along with a new strong gauge interaction capable of breaking the electroweak gauge symmetry dynamically were recently introduced under the name of katoptrons. Their main function is to provide a viable alternative to the Standard-Model Higgs sector. In such a framework, ordinary fermions acquire masses after the breaking of the strong katoptron group which allows mixing with their katoptron partners. The purpose of this paper is to study the elementary-scalars-free mechanism responsible for this breaking and its implications for the fermion mass hierarchies.Comment: 15 LaTeX pages, some comments added, version published in Modern Physics Letters

    Phase mixing of a three dimensional magnetohydrodynamic pulse

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    Phase mixing of a three dimensional magnetohydrodynamic (MHD) pulse is studied in the compressive, three-dimensional (without an ignorable coordinate) regime. It is shown that the efficiency of decay of an Alfvénic part of a compressible MHD pulse is related linearly to the degree of localization of the pulse in the homogeneous transverse direction. In the developed stage of phase mixing (for large times), coupling to its compressive part does not alter the power-law decay of an Alfvénic part of a compressible MHD pulse. The same applies to the dependence upon the resistivity of the Alfvénic part of the pulse. All this implies that the dynamics of Alfvén waves can still be qualitatively understood in terms of the previous 2.5D models. Thus, the phase mixing remains a relevant paradigm for the coronal heating applications in the realistic 3D geometry and compressive plasma

    Star-forming Galactic Contrails at z=3.2 as a Source of Metal Enrichment and Ionizing Radiation

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    A spectroscopically detected Lyman alpha emitting halo at redshift 3.216 in the GOODS-N field is found to reside at the convergence of several Lyman alpha filaments. HST images show that some of the filaments are inhabited by galaxies. Several of the galaxies in the field have pronounced head-tail structures, which are partly aligned with each other. The blue colors of most tails suggest the presence of young stars, with the emission from at least one of the galaxies apparently dominated by high equivalent width Lyman alpha. Faint, more diffuse, and similarly elongated, apparently stellar features, can be seen over an area with a linear extent of at least 90 kpc. The region within several arcseconds of the brightest galaxy exhibits spatially extended emission by HeII, NV and various lower ionization metal lines. The gas-dynamical features present are strongly reminiscent of ram-pressure stripped galaxies, including evidence for recent star formation in the stripped contrails. Spatial gradients in the appearance of several galaxies may represent a stream of galaxies passing from a colder to a hotter intergalactic medium. The stripping of gas from the in-falling galaxies, in conjunction with the occurrence of star formation and stellar feedback in the galactic contrails suggests a mechanism for the metal enrichment of the high redshift intergalactic medium that does not depend on long-range galactic winds, at the same time opening a path for the escape of ionizing radiation from galaxies.Comment: 12 pages, 9 figures, submitted to MNRA

    Age Related Changes in Cerebrovascular Reactivity and Its Relationship to Global Brain Structure

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    ACKNOWLEDGMENTS This study was funded by Alzheimer’s Research UK (ARUK) and the Aberdeen Biomedical Imaging Centre, University of Aberdeen. GDW, ADM and CS are part of the SINASPE collaboration (Scottish Imaging Network - A Platform for Scientific Excellence www.SINAPSE.ac.uk). The authors thank Gordon Buchan, Baljit Jagpal, Nichola Crouch, Beverly Maclennan and Katrina Klaasen for their help with running the experiment and Dawn Younie and Teresa Morris for their help with recruitment and scheduling. We also thank the residents of Aberdeen and Aberdeenshire, and further afield, for their generous participation.Peer reviewedPublisher PD

    Nature of eclipsing pulsars

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    We present a model for pulsar radio eclipses in some binary systems, and test this model for PSRs B1957+20 and J2051-0827. We suggest that in these binaries the companion stars are degenerate dwarfs with strong surface magnetic fields. The magnetospheres of these stars are permanently infused by the relativistic particles of the pulsar wind. We argue that the radio waves emitted by the pulsar split into the eigenmodes of the electron-positron plasma as they enter the companion's magnetosphere and are then strongly damped due to cyclotron resonance with the ambient plasma particles. Our model explains in a natural way the anomalous duration and behavior of radio eclipses observed in such systems. In particular, it provides stable, continuous, and frequency-dependent eclipses, in agreement with the observations. We predict a significant variation of linear polarization both at eclipse ingress and egress. In this paper we also suggest several possible mechanisms of generation of the optical and XX-ray emission observed from these binary systems.Comment: 12 pages, 5 figures, submitted to Ap

    Penegakan Hukum Bagi Pelaku Pengeboman Ikan di Kabupaten Flores Timur

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    This research aims is to study about the law enforcement for fishermen who catch fishes with bomb in East Flores Regency. The research method uses empirical juridical. The data consist of primary and secondary data. Data are analysed by using qualitative analysis. The research results conclude that the law enforcement for fishermen who catch fishes with bomb in East Flores Regency are repressive, preventive and curative efforts. The most law enforcement is the repressive effort. The obstacles in this law enforcement are limited number of police personnel and the lack of facilities and infrastructure. Keywords : Law Enforcement, Fishermen, Bombs. Penelitian ini bertujuan untuk mengkaji penegakan hukum bagi pelaku yang menangkap ikan dengan menggunakan bom. Metode penelitian menggunakan yuridis empiris. Data yang digunakan dalam penelitian ini terdiri dari data primer dan data sekunder. Seluruh data dianalisis menggunakan analisis kualitatif. Hasil penelitian menyimpulkan bahwa penegakan hukum yang dilakukan oleh sub sistem Peradilan Pidana di Kabupaten Flores Timur meliputi upaya represif, preventif dan juga kuratif. Penegakan hukum yang paling banyak dalam bentuk upaya represif. Kendala kendala yang dihadapi dalam penegakan hukum ini meliputi jumlah personil kepolisian yang terbatas dan kurangnya sarana dan prasarana
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